@article{ChristlBruentrup1974, author = {Christl, Manfred and Br{\"u}ntrup, Gisela}, title = {Diimine Reduction and Ozonolysis of Benzvalene}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57953}, year = {1974}, abstract = {Via reduction of benzvalene (1) with diirnine tricyclo[3.1.0.02•6]hexane is obtained in good yield. The procedure renders 3, which has already been synthesized by Lemal and Shim, accessible much easier and in larger quantities. IH and 13C n.m.r. spectroscopic data are discussed. Both the thermal and the AgBF4-catalyzed rearrangernent of 3 yield 1,3-cyclohexadiene (8). - The ozonolysis of 1 with subsequent LiAIH4-reduction results in cis-I,3- bis(hydroxyrnethyl)cyclobutane (13a).}, subject = {Organische Chemie}, language = {en} } @article{HegmannChristlPetersetal.1988, author = {Hegmann, Joachim and Christl, Manfred and Peters, Karl and Peters, Eva-Maria and Schnering, Hans Georg von}, title = {Die Reaktionskaskade von 6-Oxo-5-phenyl-1,3,4-oxadiazin-2-carbons{\"a}ure-methylester und 1,3-Butadienen zu konjugierten und nichtkonjugierten Cyclopentenonen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58421}, year = {1988}, abstract = {F{\"u}nfgliedrige Carbocyclen sind Bauelemente zahlreicher NaturstofTe und daher attraktive Syntheseziele. Da bisher kein Syntheseverfahren mit großer Anwendungsbreite bekannt ist, sind neue Methoden willkommen. Wir berichten hier {\"u}ber Umsetzungen des Titelheterocyclus 1 mit l,3-Butadienen 1; diese Reaktionen, obwohl vielstufig, liefern im Eintopfverfahren konjugierte und nichtkonjugierte Cyclopentenone und gestatten auch die F{\"u}nfringanellierung.}, subject = {Organische Chemie}, language = {de} } @article{EngelsPeyerimhoff1989, author = {Engels, Bernd and Peyerimhoff, S.D.}, title = {Theoretical study of FC\(_2\)H\(_4\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58824}, year = {1989}, abstract = {Large-scale multireference configuration interaction (MRD-CI) calculations in a quite flexible AO basis are employed to study the energy hypersurface for the reaction intermediate FC\(_2\)H\(_4\) • The reaction F + C\(_2\)H\(_4\) -> FC\(_2\)H\(_4\) as weil as the 1,2 migration of the fluorine atom in FC\(_2\)H\(_4\) is investigated. In addition the rotation around the CC bond in the optimum conformation is studied. The absolute minimum in the potential energy is found for the asymmetric structure but the symmetric structure is also found to be stable with respect to the dissociation, so that a shuttling of the fluorine atom is in principle possible but highly unlikely because ( l) the activation energy is high ( II 5-130 kJ fmol) and the saddle point lies only 4(}-50 kJ jmol below the dissociation Iimit of F + C\(_2\)H\(_4\) and (2) the competitive motion, i.e., rotation around the CC axis, is nearly free (I 1-17 kJ/mol).}, subject = {Organische Chemie}, language = {en} } @article{EngelsPeyerimhoff1989, author = {Engels, Bernd and Peyerimhoff, S.D.}, title = {The hyperfine coupling constants of the X\(^3\)Σ\(^-\) state of NH : Influence of polarization functions and configuration space on the description of spin polarization}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58832}, year = {1989}, abstract = {The hyperfine coupling constants for the \(^3\)Σ\(-\) ground state of the NH molecule are determined by configuration interaction calculations whereby the infl.uence of polarization functions as weil as of the configuration space on the spin polarization mechanism is analysed. The dipolar part Au(N) and Au(H) can be obtained very reliably without much computational effort (A .. (N) == -45·3 MHz and A"(H) = -62·3 MHz). The value for the isotropic contribution a1.., in the best AO basis and MRD-CI treatment is - 64·5 MHz for H and 16·6 MHz for nitrogen compared to the corresponding experimental quantities of -66 MHz and 19 MHz respectively. Their determination depends on a subtle balance of the lu, 2u and 3u shell correlation description, whereby the dominant contribution to a1..,(H) results from the 2u shell. It is shown that the often good agreement of a110 values with experiment in a small basis singledouble configuration interaction treatment results from a cancellation of two errors.}, subject = {Organische Chemie}, language = {en} } @article{EngelsPeyerimhoff1989, author = {Engels, Bernd and Peyerimhoff, S.D.}, title = {Study of orbital transformations in configurational interaction calculation of hyperfine coupling in nitrogen and CH molecule}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58847}, year = {1989}, abstract = {Multi-reference configuration interaction calculations employing various orbital transformations are undertaken to obtain the isotropic hyperfine coupling constant a\(_{iso\) in nitrogen and a\(_{iso\) (H) in the CH molecule. The natural orbital (NO) basis is found to be more effective than the simple RHF-MO basis; the most obvious is a basis of spin natural orbitals (SNO). It is found that a\(_{iso\) is approached from opposite sides in the NO and 2s shell SNO basis if the CI expansion is increased. Both results are within a few percent of the full CI Iimit for the nitrogen atorn (in the given AO basis) and the experimental value for Hin the CH radical. Various features ofthe SNO are discussed.}, subject = {Organische Chemie}, language = {en} } @article{EngelsPeyerimhoffSkell1990, author = {Engels, Bernd and Peyerimhoff, S.D. and Skell, P.S.}, title = {Theoretical study of the potential energy surface governing the stereochemistry in ClC\(_2\)H\(_4\) reactions}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58851}, year = {1990}, abstract = {Large-scale multireference configuration interaction calculations in a double·t·type AO basis including polarization functions are carried out for the potential surface of the ClC\(_2\)H\(_4\9 system. The charge distribution for various extreme points of the surface is discussed. The absolute minimum is found for an asymmetric ClC2H4 structure. The symmetrical bridged nuclear conformation is also found to be stable with respect to dissociation into Cl + C\(_2\)H\(_4\)• The activation energy for rotation about the C-C axis is calculated tobe around 18 kJ/mol, which is comparable tothat for the 1,2 migration {around 26 kJ/mol). The stereochemistry is governed by the fact that addition of CI to C\(_2\)H\(_4\) (or dissociation) is a two-step reaction proceeding through a symmetrica1 intermediate. The direct addition pathway possesses a small barrier of about 8 kJ jmol.}, subject = {Organische Chemie}, language = {en} } @article{LeiningerLanzendoerferChristl1983, author = {Leininger, H. and Lanzend{\"o}rfer, F. and Christl, Manfred}, title = {{\"U}ber die Reduktion des Benzvalenozonids zum cis-1,3-Cyclobutandimethanol mit LiAlH\(_4\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58130}, year = {1983}, abstract = {No abstract available}, subject = {Organische Chemie}, language = {en} } @article{LeiningerChristlWendisch1983, author = {Leininger, H. and Christl, Manfred and Wendisch, D.}, title = {{\"U}ber die Oxidation von Benzvalen mit Singulett-Sauerstoff zum Bicyclo[1.1.0]butan-endo,endo-2,4-dicarbaldehyd}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58142}, year = {1983}, abstract = {No abstract available}, subject = {Organische Chemie}, language = {de} } @article{ChristlLanzendoerferPetersetal.1983, author = {Christl, Manfred and Lanzend{\"o}rfer, F. and Peters, K. and Peters, E.-M. and Schnering, H. G. von}, title = {Die Reaktionen von 2,5-Diaryl-1,3,4-oxadiazin-6-onen mit trans-Cycloocten, cis,trans-Cyclooctadien und Cyclopropenen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58156}, year = {1983}, abstract = {The transient [4+2]-cycloadducts from the title components eliminate nitrogen to form a 3,4-dihydro-2-pyrone derivative, a tricyclic cyclobutanone derivative and 2,5-dihydrooxepin-2-one derivatives, respectively.}, subject = {Organische Chemie}, language = {de} } @article{ChristlLangReimannetal.1984, author = {Christl, Manfred and Lang, R. and Reimann, W. and Irngartinger, H.}, title = {Darstellung und R{\"o}ntgenstrukturanalyse des Diels-Alder-Addukts von 4-Phenyl-4H-1,2,4-triazol-3,5-dion an Octavalen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58162}, year = {1984}, abstract = {No abstract available}, subject = {Organische Chemie}, language = {de} }